There is a storage system including multiple host apparatus and multiple storage devices connected over a network through switch devices. In the storage system, the host apparatus and the storage devices exchange data. The switch devices in the storage system are connected redundantly for higher fault tolerance.
The technology for effectively using storage areas of storage devices in the storage system may include a virtualization technology for storage apparatus. The virtualization of storage devices may be managed through switch devices. The management of virtualization of storage devices through switch devices allows a combination of multiple storage devices and reduction of management of storage devices in the host apparatus. A technique related to the above techniques is discussed in Japanese Laid-open Patent Publication No. 2006-72981.
The switch devices may perform snapshot processing that copies the state of data at a certain point, which is stored in a virtual storage area, to another virtual storage area. In the snapshot processing, the completion of the copying is notified without waiting for the completion of the processing of copying real data. After the notification, the switch device performs actual copy processing.
For that reason, even during the snapshot processing by one switch device, the other switch devices can access the storage area being the subject of the snapshot processing, which may cause inconsistency in the data in the target storage area.